Mario Manningham had scuffled through his worst season as a pro, suffered from a concussion and knee woes and plain old-fashioned rust. But after he caught a jaw-dropping, game-clinching touchdown to seal the Giants’ 24-2 NFC Wild Card rout of Atlanta, none of that seemed to matter.

The wide receiver had four receptions for 68 yards, including his 27-yard fourth-quarter grab for his first postseason touchdown. And afterward, finally fit and healthy, he sounded as if he was ready to take on the top-seeded Packers today.

“Let’s just keep going, keep winning,” Manningham said. “We’re playing good and we’re a hard team to beat. We’ve got to just keep going and don’t let up… I can’t wait to get up there and do what we’ve got to do.’’

Who could blame Manningham? Not after a performance like this. He finished the regular season with 39 catches for 523 yards and four touchdowns, his lowest production since becoming a full-time player in 2009. He missed four games, suffering a concussion Sept. 19 and missing the next game, then missing games Nov. 28 and Dec. 4 because of a knee injury.

He had not caught a pass since Dec. 18 and had caught just six since Nov. 13, but he had a huge impact yesterday.

“I’m so happy for him,’’ said Victor Cruz, who has supplanted Manningham as the Giants’ No. 2 receiver. “He’s battled through injuries this year, for him to come out and do some good things, I’m just proud of my guys.’’

Cruz had drawn the headlines coming in, but was held to just two catches for 28 yards as Manningham and Hakeem Nicks (six catches for 115 yards and a TD) dominated the Falcons’ secondary.

“How about Mario?’’ coach Tom Coughlin said. “Mario had a big day and he played well. He really worked the sideline and he caught that really nice over-the-top pass from Eli.’’

That over-the-top pass was flawless, with Eli Manning lining up in the shotgun and feathering a perfect throw over safety James Sanders for a touchdown with 10:04 left that sealed the win.

“He threw it out there and I just went and got it,’’ said Manningham. “As a receiving corps, it’s our first playoff game, so we’re a little excited. … When all three of us are out there, we’re a hard receiving corps to stop.’’